In order for making microstructures of high aspect ratio, there are many processes, including LIGA, LIGA like, UV photolithography, etc., ever being disclosed for such a purpose. However, such conventional processes are complex and expensive so that they are uneconomic and infeasible on a commercial point of view.
A conventional process for manufacturing high aspect ratio microstructures was disclosed by using a trench-filling etch masking technique by etching deep trenches into a substrate, filling trench filling material in the trenches, and deep etching into the substrate being carried out with the trench-filling material serving as a mask. However, such a prior art requires many process steps for finishing the microstructures, still being time-consuming and lowering production efficiency.
The present inventor has found the drawbacks of the conventional processes, and invented the present microfabrication process more economic and feasible for making microstructures.